The invention pertains to an apparatus for keeping down the groundcover between parallel rows of plants, in particular rows of wine grape or fruit plants, with two chopping blade rotors rotating in one and the same plane, each around an axis perpendicular to the ground, wherein the distance between the rotational axes perpendicular to the plant rows is adjustable even though the areas in which the chopping blade rotors rotate may overlap.
Apparatuses of this type, so-called mulchers, are known through use. The chopping blade rotors of these known mulchers, intended to be coupled to small tractors, are driven by a shaft connected to the tractor. The rotation of this power take-off shaft is first transmitted to a hex shaft by a central gearbox of the mulcher and then by the hex shaft to the gearboxes of the mulcher assigned to the chopping blade rotors. When the distance between the rotational axes of the chopping blade rotors is adjusted, these gearboxes shift along the hex shaft together with the chopping blade rotors.
When accidents occur, especially collisions of the individual blades of the chopping blade rotors with obstacles on the ground, the gearboxes assigned to the chopping blade rotors are put at risk. In cases where the chopping blade rotors rotate in one and the same plane, slip clutches between the chopping blade rotors and the gearbox which could dampen the effects of impacts cannot be used.